PAR1 Scaffolds TGFβRII to Downregulate TGF-β Signaling and Activate ESC Differentiation to Endothelial Cells

Abstract

SummaryWe studied the function of the G-protein-coupled receptor PAR1 in mediating the differentiation of mouse embryonic stem cells (mESCs) to endothelial cells (ECs) that are capable of inducing neovascularization. We observed that either deletion or activation of PAR1 suppressed mouse embryonic stem cell (mESC) differentiation to ECs and neovascularization in mice. This was mediated by induction of TGFβRII/TGFβRI interaction, forming an active complex, which in turn induced SMAD2 phosphorylation. Inhibition of TGF-β signaling in PAR1-deficient mESCs restored the EC differentiation potential of mESCs. Thus, PAR1 in its inactive unligated state functions as a scaffold for TGFβRII to downregulate TGF-β signaling, and thereby promote ESC transition to functional ECs. The PAR1 scaffold function in ESCs is an essential mechanism for dampening TGF-β signaling and regulating ESC differentiation.

Lineage specification and pluripotency revealed by transcriptome analysis from oocyte to blastocyst in pig

“…27 However, in consistent with the GO enrichment and KEGG pathways analysis, except RAF1, all the members checked in the pathway were significantly high in ICM ( Figure 5C), indicating MAPK signalling pathway may be important for the further progression of ICM. 29 We observed the receptors (TGFβR1 and TGFβR2) and the mediators (SMAD2 and SMAD3) checked in the pathway were all significantly low expressed in ICM, and the inhibitor of TGFβ, LEFTY2 was significantly high in ICM ( Figure 5F), suggesting the pathway should be suppressed in naïve pluripotency of pig. We also looked at the profile of the JAK-STAT signaling pathway ( Figure 5D).…”

“…Lastly, we investigated the TGFβ pathway, which is essential for human ESC self-renewal, 1,28 but should be inhibited in mouse ESC with naïve pluripotency. 29 We observed the receptors (TGFβR1 and TGFβR2) and the mediators (SMAD2 and SMAD3) checked in the pathway were all significantly low expressed in ICM, and the inhibitor of TGFβ, LEFTY2 was significantly high in ICM ( Figure 5F), suggesting the pathway should be suppressed in naïve pluripotency of pig. Collectively, the results demonstrate that the function of ICM in pig should be dependent on the activity of JAK-STAT, MAPK and PI3K-AKT signaling pathways.…”

The regulators of G protein signaling RGS16 and RGS18 inhibit protease‐activated receptor 2/Gi/o signaling through distinct interactions with Gα in live cells

“…PAR1 binds transforming growth factor b (TGF-b) receptor II (TGFR-bII) and inhibits dimerization of TGFR-bI/TGFR-bII, which leads to downregulation of TGF-b signaling and modulation of embryonic stem cell differentiation [12]. PAR1 binds transforming growth factor b (TGF-b) receptor II (TGFR-bII) and inhibits dimerization of TGFR-bI/TGFR-bII, which leads to downregulation of TGF-b signaling and modulation of embryonic stem cell differentiation [12].…”

“…G protein-coupled receptors function as scaffolding proteins that interact with several signaling molecules. PAR1 binds transforming growth factor b (TGF-b) receptor II (TGFR-bII) and inhibits dimerization of TGFR-bI/TGFR-bII, which leads to downregulation of TGF-b signaling and modulation of embryonic stem cell differentiation [12]. Gpr161, an orphan GPCR, contains a motif for A-kinase anchoring protein in its C-terminal tail and binds the regulatory subunits of PKA, leading to the modulation of cAMP signaling [13].…”

G Protein-Coupled Receptors at the Crossroad between Physiologic and Pathologic Angiogenesis: Old Paradigms and Emerging Concepts

“…GPCRs other than the ones classically involved in self-renewal, quiescence and differentiation have been implicated in the endothelial differentiation and in the hematopoietic process, which together contribute to maintain homeostasis within the vascular system. For instance, a GPCR gene expression screen performed in mouse embryonic stem cells (mESCs) has identified PAR1 as the crucial GPCR involved in cell reprograming toward an endothelial phenotype [ 29 ]. Extending these observations, regulation of lineage specification and homing, together with preservation of self-renewal capacity and expansion of hematopoietic stem and progenitor cells (HSPCs) are regulated by several members of the rhodopsin family, such as chemokine C-X-C motif receptor 4 (CXCR4), sphingosine-1-phosphate receptor (S1PR1/EDG1), and prostaglandin receptor (EP2), and a member of the glutamate family (calcium sensing receptor CaSR) [ 91 , 92 , 93 , 94 , 95 , 96 ].…”